How can I get the secret achievements?

Secret Mission 01: Gate Crasher (Stage 1)

Gate Crasher

Awarded for smashing all of the chandeliers in Guppy's Mansion


Secret Mission 02: Anti-Omelette (Stage 2)

Anti-Omelette

Awarded for not breaking any of the eggs in the Lava Caves


Secret Mission 03: Lil' Mama (Stage 3)

Lil' Mama

Awarded for not tripping any of the lasers in the High Security Complex


Secret Mission 04: Speed Demon (Stage 4)

Speed Demon

This achievement appears to be awarded for completing the level under a certain time. The exact length of time is not currently known.


Secret Mission 05: Preferred Polarity (Stage 5)

Preferred Polarity

I got this one by not killing any enemies in the first segment of the Top Secret Lab, but the icon seems to indicate that all you need to do is avoid killing any red ones.


Secret Mission 06: Clean Shoes (Stage 6)

Clean Shoes

Awarded for not landing on any of the membrane inside the Dragon

Membrane


Secret Mission 07: Perfect Pacifist (Stage 7)

Perfect Pacifist

Awarded for reaching the top of the Hall of Heroes without killing any enemies or taking damage


Secret Mission 04: Speed Demon. Acquired by completing the level in a certain amount of time. Most easily done by setting the difficulty to Easy and rushing through the level, not stopping to fight.